A new glow.
On 11 January 1949, a patent was approved for use by Panerai under the name "Luminor", for all the luminescent and self-luminescent materials used. Giuseppe Panerai realised that the connection with radioactivity had to be treated with caution, considering the new reality created by the expansion of impressive military and civilian atomic technologies.
After more than a decade, Luminor was recognised as a new luminescent substance based on tritium (an isotope of hydrogen), with very low emissions and harmless, replacing Radiomir, the initial substance that used radium-226.
And Luminor gradually became, by convention, the name of the Panerai diving watch, characterised by the crown-protection bridge. This last invention was patented in Italy in 1955 as the "Tight Seal Device" by its inventors, the brothers Giuseppe and Maria Giuseppe Panerai.